Thermal cut-out plug



Mmh s, 1932. H, F, TAL T 1,848,677

' THERMAL CUT-OUT PLUG Filed Nov. 22, 1929 Patented Mar. 8, 1932 rUNITED STATES PATENT OFFICE BARBIE F. TALBOT, OF PERU, ILLINOIS,ASSIGNOB TO DIAL-COMPANY, 0! NEW YORK, N. Y., A CORPORATION OF DELAWARE'rnnnmr. cu'r-ou'r PLUG Application filed November 22, 1929. Serial No.409,030.

' This invention relates to electric plugs, and more particularly toacut-out plug of the circuit-breaker type in which the circuit will beautomatically broken when the current reaches a certain amount withoutinjury to any of the parts of the plug.

One object of the invention is to provide a circuit breaker plug of theabove nature employing a bimetallic latch and spring catch which may berestored to operating position after the circuit has been broken bymanually twisting the cap and without requiring replacement of any ofthe parts thereof.

A further object is to provide a device of the above nature which willbe simple in construction, inexpensive to manufacture, easy to assembleand manipulate. and Very ellicient and durable in use.

With these and other objects in view,there has been illustrated on theaccompanying drawings one form in which the invention may beconveniently embodied in practice.

Fig. 1 represents a vertical longitudinal sectional view of the cut-outplug.-

Fig. 2 is a similar longitudinal sectional view of the same, the sectionbeing taken at right angles from the view of Fig. 1.

Fig. 3 is a transverse horizontal sectional view taken along the line 33of Fig 2 looking downwardly, and showing the bimetallic latch out ofengagement with the top of the spring catch.

Fig. 4 is a transverse sectional view, similar to Fig. 3 showing thebimetallic latch in locking Iengagement with the top of the spring catcReferring now to the drawings in which like reference numerals denotecorresponding parts throughout the several views, the numeral 10indicates a circular body shell of insulating material, said body shellbeing provided with a downwardly extending slot 11 in one side thereof.The outer periphery of the body shell 10 is provided near its top with arectangular groove 12, which is adapted to receive a resilient curvedstrip metal spring- 13 surrounding substantially three quarters of thecircumference of the base of the slot 12. The spring 13 has one end bentover at 14, said end 14 having an aperture 15 for receiving a set-screw16 threaded into an aperture 17 formed in a cup-shaped cover member orcap 18, also of insulating material.

By means of this construction, it will be seen ed to receive an outermetallic shell contact 19 which has an inturned bottom flange 20 adaptedto seat in a groove'2l in an insulating base member 22 located below thebody shell 10.

In order to form a base terminal for the cut-out plu provision, is madeof a tubular member 23 aving an enlarged lower section 24 for engagementwith the center contact of an electric socket. The construction of thisbase terminal has been described and claimed in a previous patentapplication by the same inventor.

Within the interior of the body shell 10 provision is made of an angularsupporting member 25 having a bottom horizontal arm 26 securedupon thebase 22 by heading over the top of the tubular section 23. The uppervertical arm 26a of the angular supporting member 25 is attached as by arivet 26b to a downturned portion 27 of a bimetallic expansion latch 28.The free end 29 of the latch 28 is downturned and pointed for engagementwith a groove 30 formed in the top of a spring catch 31, the latterhaving its lower end reversely bent upwardly at 32, and said upwardlybent end 32 is held securely in position between the outer portion ofthe body shell 10 and the shell contact 19.

Operation part of the spring catch 31 forcing it inwardly until it snapsinto locking engagement with the down-turned portion 27 of the latch 28.While there has been disclosed in this specification one form in whichthe invention may be embodied, it is to be understood that this form isshown for the purpose of illustration only, and that the invention isnot to be limited to the specific disclosure but may be modified andembodied in .various other forms without departing from its spirit. Inshort, the invention includes all the modifications and embodimentscoming within the sccipe of the following claims.

avingthus-fully described the invention, what is claimed as new, and forwhich it is desired to secure Letters Patent, is:

1. In a cut-out plug, an insulating base member, a central contactterminal and a shell contact terminal secured to said base member, anangular supporting member on said base connected with said centralterminal, a bimetallic latch secured to the top of said supportingmember and having a downturned extremity, a spring catch having agooveat its upper end extending upwardly om said outer shell terminal,said latch normally engaging said catch to close the circuit, sa1d latchbeing automatically raised out of contact with said catch when thecurrent through the cuteout exceeds a safe limit.

2. In a cut-out plug, an insulating base member, a central contactterminal and a shell contact terminal secured to said base member, anangular supporting member on said base connected with said centralterminal, a bimetallic latch secured to the top of said supportingmember and having a downturned extremity, a spring catch extendingupwardly from said outer shell terminal, said latch normally engagingsaid catch to close the circuit, said latch being automatically raisedout of contact with said catch when the current through the fuse exceedsa safe limit, an outer insulating body shell, a cap on said body shellhaving a down- .wardly extending flange, and means in said flange toconnect said latch and catch by manually rotating said cap after thecircuit has been broken.

3. In a cut-out plug, an insulating base member, a central contactterminal and a shell contact terminal secured to said base member, anangular supporting member on said base connected with said centralterminal, a bimetallic latch secured to the top of said supportingmember and having a downturned extremlty, a spring catch extendingupwardly from said outer shell terminal, said latch normally engagingsaid catch to close the circuit, said latch being automatically raisedout of contact with said catch when the current through the fuse exceedsa safe limit, an outer insulating body shell, a cap the circuit, saidlatch on said body shell having a downwardly extending flange, and meansin said flange to connect said latch and catch by manually rotating saidcap after the circuit has been broken.

4;. In a cut-out plug, an insulating base member, a central contactterminal and a shell contact terminal secured to said base member, anangular supporting member on said base connected with said centralterminal, a bimetallic latch secured to the top of said supportingmember and having a downturned extremity, a spring catch extendingupwardly from said outer shell terminal, said latch normally engagingsaid catch to close the circuit, said latch being automatically raisedout of contact with said catch when the current through the fuse exceedsa safe limit, an outer insulating body shell, a

cap on said body shell having a downwardly extending flange, and aspring strip in said flange to connect said latch and catch by manuallyrotating said cap after the circuit has been broken.

5. In a cut-out plug, an insulating base member, a central contactterminal and a shell contact terminal secured to said base member, anangular supporting member on said base connected with said centralterminal, a bimetallic latch secured to the top of said supportingmember and having a downi turned extremity, a spring catch extendingupwardly fromsaid outer shell terminal, said latch normally engagin saidcatch to close eing automatically raised out of contact with said catchwhen the current through the fuse exceeds a safe limit, an outerinsulating body shell, a cap on said body shell having a downwardlyextending flange, and a spring strip in said flange to connect saidlatch and catch by manually rotating said cap after the circuit has beenbroken.

In testimony whereof, I have aflixed my signature to this specification.

HARRIE F. TALBOT.

